/*
 * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
 *
 * This file is part of MjSip (http://www.mjsip.org)
 *
 * MjSip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MjSip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MjSip; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author(s):
 * Luca Veltri (luca.veltri@unipr.it)
 */

package org.zoolu.net;


import android.os.Looper;
import android.util.Log;

import java.io.IOException;
import java.io.InterruptedIOException;


/** UdpProvider provides an UDP send/receive service.
 * On the receiver side it waits for UDP datagrams and passes them
 * to the UdpProviderListener.
 * <p> If the attribute <i>alive_time</i> has a non-zero value, the UdpProvider stops
 * after <i>alive_time</i> milliseconds of inactivity.
 * <p> When a new packet is received, the onReceivedPacket(UdpProvider,DatagramPacket)
 * method is fired.
 * <p> Method onServiceTerminated(UdpProvider) is fired when the the UdpProvider stops
 * receiving packets.
 */
public class UdpProvider extends Thread
{
    /** The reading buffer size */
    public static final int BUFFER_SIZE=65535;

    /** Default value for the maximum time that the UDP receiver can remain active after been halted (in milliseconds) */
    public static final int DEFAULT_SOCKET_TIMEOUT=2000; // 2sec

    /** UDP socket */
    protected UdpSocket socket;

    /** UdpProvider listener */
    protected UdpProviderListener listener;

    /** Maximum time that the UDP receiver can remain active after been halted (in milliseconds) */
    int socket_timeout;

    /** Maximum time that the UDP receiver remains active without receiving UDP datagrams (in milliseconds) */
    long alive_time;

    /** Minimum size for received packets. Shorter packets are silently discarded. */
    int minimum_length;

    /** Whether it has been halted */
    boolean stop;

    /** Whether it is running */
    boolean is_running;


    /** Creates a new UdpProvider */
    public UdpProvider(UdpSocket socket, UdpProviderListener listener)
    {  init(socket,0,listener);
        start();
    }


    /** Creates a new UdpProvider */
    public UdpProvider(UdpSocket socket, long alive_time, UdpProviderListener listener)
    {  init(socket,alive_time,listener);
        start();
    }


    /** Inits the UdpProvider */
    private void init(UdpSocket socket, long alive_time, UdpProviderListener listener)
    {  this.listener=listener;
        this.socket=socket;
        this.socket_timeout=DEFAULT_SOCKET_TIMEOUT;
        this.alive_time=alive_time;
        this.minimum_length=0;
        this.stop=false;
        this.is_running=true;
    }


    /** Gets the UdpSocket */
    public UdpSocket getUdpSocket()
    {  return socket;
    }


    /** Sets a new UdpSocket */
   /*public void setUdpSocket(UdpSocket socket)
   {  this.socket=socket;
   }*/


    /** Whether the service is running */
    public boolean isRunning()
    {  return is_running;
    }


    /** Sets the maximum time that the UDP service can remain active after been halted */
    public void setSoTimeout(int timeout)
    {  socket_timeout=timeout;
    }


    /** Gets the maximum time that the UDP service can remain active after been halted */
    public int getSoTimeout()
    {  return socket_timeout;
    }


    /** Sets the minimum size for received packets.
     * Packets shorter than that are silently discarded. */
    public void setMinimumReceivedDataLength(int len)
    {  minimum_length=len;
    }


    /** Gets the minimum size for received packets.
     * Packets shorter than that are silently discarded. */
    public int getMinimumReceivedDataLength()
    {  return minimum_length;
    }


    /** Sends a UdpPacket */
    public void send(UdpPacket packet) throws IOException
    {  if (!stop) socket.send(packet);
    }


    /** Stops running */
    public void halt()
    {  stop=true;
    }


    /** The main thread */
    public void run() {
        byte[] buf = new byte[BUFFER_SIZE];
        UdpPacket packet = new UdpPacket(buf, buf.length);

        Exception error = null;
        long expire = 0;
        if (alive_time > 0) expire = System.currentTimeMillis()+alive_time;
        try {
            socket.setSoTimeout(socket_timeout);
            // loop
            while(!stop) {
                try {
                    socket.receive(packet);
                }
                catch (InterruptedIOException ie) {
                    if (alive_time>0 && System.currentTimeMillis() > expire) halt();
                    continue;
                }
                if (packet.getLength() >= minimum_length) {
                    if (listener != null) listener.onReceivedPacket(this,packet);
                    if (alive_time > 0) expire=System.currentTimeMillis()+alive_time;
                }
                packet = new UdpPacket(buf, buf.length);
            }
        }
        catch (Exception e) {
            error = e;
            stop=true;
        }

        is_running = false;
        if (listener != null) listener.onServiceTerminated(this, error);
        listener = null;
    }

    /** Gets a String representation of the Object */
    public String toString()
    {  return "udp:"+socket.getLocalAddress()+":"+socket.getLocalPort();
    }

}
